Appendix B Troubleshooting Measurement Errors; Troubleshooting Measurement Errors From Electromagnetic Fields - Sigma 980 Operating And Maintenance Manual

Appendix B

Troubleshooting Measurement Errors From Electromagnetic Fields

Offending Frequency
(mega Hz)
90.5
119
141
392
Offending Frequency
(mega Hz)
84
93.7
105
125
127
131
150
324
382
Offending Frequency
(mega Hz)
31.43
44.94
374.00
Troubleshooting Measurement Errors
Measurement inaccuracy can be affected by numerous factors, one of these
factors is Radio Frequency (RF). The 980 Flow Meter is designed to be
resistant to RF fields and other Electromagnetic Interference (EMI), however,
RF fields at certain frequencies (at or above 10 Volt/per meter level) can
cause disturbances to measurement circuits causing inaccurate
measurements. If RF is causing measurement errors, the tranmitter(s) are
usually located near the 980 Flow Meter. When the transmitter(s) are too
close to the instrument, remove or move the transmitter farther away from the
980 Flow Meter.
The following tables provide RF frequencies and levels that can cause
measurement errors. Compare any local transmitters and its transmitting
frequency to the tables listed below.
Analog Input
Measurement Error
(milli V)
28
12
11
9
Temperature
Measurement Error
(°C)
1.9
2.1
5.6
3.6
2.2
3.8
2.3
1.9
7.5
Level Accuracy
Measurement Error
(inch)
1.300
0.430
0.780
Specification
(milli V)
not specified
not specified
not specified
not specified
Specification
(°C)
not specified
not specified
not specified
not specified
not specified
not specified
not specified
not specified
not specified
Specification
(inch)
0.36
0.36
0.36
Troubleshooting Measurement Errors
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